A data bus can be utilized for interconnecting electronic devices such as computers, audio systems, television receivers, display devices, video recorders, and home control devices such as security system or appliance control systems. Communication using a data bus occurs in accordance with a bus protocol recognized by devices attached to the bus. Examples of bus protocols include the IEEE 1394 High Performance Serial Bus and the Universal Serial Bus (USB). A bus protocol typically provides for communicating both control information and data. On an IEEE 1394 serial bus, control information is generally passed using the asynchronous services of the serial bus. Control information for a particular application can be defined using, for example, Common Application Language (CAL) or Audio-Video/Control (AV/C).
Like video processing, in audio processing applications, audio samples can be packed in the order the samples enter an audio processing engine. The order could be by stereo pairs, mono channels, interleaved channels, or whatever order the audio hardware chooses to packetize the audio data. This places a significant processing burden on the packetizer or depacketizer to determine which audio channel buffer is associated with each audio sample in the packet. The complexity is further compounded when multiple devices transmit audio data to the audio processing engine, as the different devices do not conform to a single standard or sample ordering. Rather, existing audio devices order the audio samples within the packet as efficiently as possible for themselves, and this efficiency does not necessarily apply to the target device that receives the audio packets.
While device descriptors are commonly used on the communication bus, current device descriptors can only describe the channel ordering used to insert audio samples in the packet, this only works for in-order processing. With multiple devices, there are multiple channel orderings, so there is a question as to how to handle all possible sample orderings and interleaved as well as non-interleaved buffers. As there is no current solution to this problem, the burden on the audio processing engine remains, and device performance suffers.